fossil

Fossilized bivalve shell

Recrystallized calcium-carbonate shell, commonly fossil oyster or clam (Bivalvia)

AI-generated identification · may be incorrect

Composed mainly of calcite/aragonite (CaCO₃), with a pale cream color, dull to waxy luster, irregular layered sculpture, and locally porous texture; Mohs hardness about 3. It appears silicified or mineral-infilled in places, but the image alone cannot determine the exact species.

Identified September 7, 2026More fossil →

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Physical properties

Formation & geological history

A marine bivalve shell was buried in sediment and preserved through mineral replacement, recrystallization, or pore filling during diagenesis. Its age cannot be established from the photograph; such fossils range from Paleozoic to Recent geological deposits.

Uses & applications

Primarily a teaching, collecting, and decorative specimen; carbonate fossils can also be crushed into aggregate or lime if abundant, though this intact example is not industrial material.

Geological facts

The raised ridges, growth bands, and shell-like bilateral form indicate a biological origin rather than an ordinary rock. Acid fizzing would support calcite, but testing may damage it.

Field identification & locations

Look for a distinct shell outline, growth lines, matching valve curvature, and carbonate composition; common sources include marine limestone, coastal sedimentary deposits, and fossil beds worldwide. Estimated value: $5–$40 for a common specimen, potentially more if exceptionally preserved or identified.